/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _SEMINIX_RATELIMIT_H
#define _SEMINIX_RATELIMIT_H

#include <seminix/param.h>
#include <seminix/sched.h>
#include <seminix/spinlock.h>

#define DEFAULT_RATELIMIT_INTERVAL	(5 * HZ)
#define DEFAULT_RATELIMIT_BURST		10

/* issue num suppressed message on exit */
#define RATELIMIT_MSG_ON_RELEASE	BIT(0)

struct ratelimit_state {
    raw_spinlock_t	lock;		/* protect the state */

    int		interval;
    int		burst;
    int		printed;
    int		missed;
    unsigned long	begin;
    unsigned long	flags;
};

#define RATELIMIT_STATE_INIT(name, interval_init, burst_init) {		\
        .lock		= __RAW_SPIN_LOCK_UNLOCKED(name.lock),	\
        .interval	= interval_init,			\
        .burst		= burst_init,				\
    }

#define RATELIMIT_STATE_INIT_DISABLED					\
    RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)

#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)		\
                                    \
    struct ratelimit_state name =					\
        RATELIMIT_STATE_INIT(name, interval_init, burst_init)	\

static inline void ratelimit_state_init(struct ratelimit_state *rs,
                    int interval, int burst)
{
    memset(rs, 0, sizeof(*rs));

    raw_spin_lock_init(&rs->lock);
    rs->interval	= interval;
    rs->burst	= burst;
}

static inline void ratelimit_default_init(struct ratelimit_state *rs)
{
    return ratelimit_state_init(rs, DEFAULT_RATELIMIT_INTERVAL,
                    DEFAULT_RATELIMIT_BURST);
}

static inline void ratelimit_state_exit(struct ratelimit_state *rs)
{
    if (!(rs->flags & RATELIMIT_MSG_ON_RELEASE))
        return;

    if (rs->missed) {
        pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
            current->comm, rs->missed);
        rs->missed = 0;
    }
}

static inline void
ratelimit_set_flags(struct ratelimit_state *rs, unsigned long flags)
{
    rs->flags = flags;
}

extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
#define __ratelimit(state) ___ratelimit(state, __func__)

#define WARN_ON_RATELIMIT(condition, state)	({		\
    bool __rtn_cond = !!(condition);			\
    WARN_ON(__rtn_cond && __ratelimit(state));		\
    __rtn_cond;						\
})

#define WARN_RATELIMIT(condition, format, ...)			\
({								\
    static DEFINE_RATELIMIT_STATE(_rs,			\
                      DEFAULT_RATELIMIT_INTERVAL,	\
                      DEFAULT_RATELIMIT_BURST);	\
    int rtn = !!(condition);				\
                                \
    if (unlikely(rtn && __ratelimit(&_rs)))			\
        WARN(rtn, format, ##__VA_ARGS__);		\
                                \
    rtn;							\
})

extern struct ratelimit_state printk_ratelimit_state;

/*
 * Please don't use printk_ratelimit(), because it shares ratelimiting state
 * with all other unrelated printk_ratelimit() callsites.  Instead use
 * printk_ratelimited() or plain old __ratelimit().
 */
extern int __printk_ratelimit(const char *func);
#define printk_ratelimit() __printk_ratelimit(__func__)

#endif /* _SEMINIX_RATELIMIT_H */
